Improvement in wood pavements



A: BETTELEY. WOOD PAVEMENT- No. 106,989. Patented Sept. 6, 1870 in: mmPerms co, noYaumo wAsqmumm o r strut mjifliw ALBERT BETTELEY, OF BOSTON,MASSACHUSETTS.

Letters Patent No. 106,989, dated September 6, 1870.

IMPROVEMENT IN WOOD PAVEMENTS.

."he Schedule referred to in these Letters Patent and making part of thesame.

To all whom it may concern I Y Be it known that I, ALBERT BETTELEY, ofBoston, in the conntyof Snfiolk and State of Massachusetts, haveinvented a new and useful Improvement 1 in Pavements; and I do herebydeclare that the following, taken in conncctiori with the drawing whichaccompanies and forms part of this specification, is a description of myinvention sufficient to enable those skilled in the art to practice it.

This invention consistsin' a pavement in which the blocks composing itare equally screw-threaded on their peripheries, so that, when placed inposition on a road-bed, the threads 'on the adjacent blocks inter lock,and the blocks thus mutually support each other, and so that, when anyportion of the pavement has to be removedfor laying pipes, sewers, 850.,or for repairs or changes of any kind, enough blocks may be takenvertically from their places, by turning them axially in the properdirection, to leave an open space, so that the majority of blocks 'to beremoved can be freed from contact with the other blocks by lateralmovement;

This pavement I consider as an improvementupon, but subordinate to thepavement patented to me Marcln29, 1870, under the number 101,346, and Idesign to construct it of wood cylinders formed from young trees,thouglrI do not consider my invention as necessarily limited to anyspecial material of which 'I may form the srr'ew-tln'eadedpavement-blocks.

In constructing screw-threaderl blocks of wood from which to make myimproved pavement, I propose to take the bodies of young trees of suchlength as can be conveniently turned in a lathe, and then, by means of acarriage moving at a fixed rate, with reference to the rotations givento the wood, I pass two tools along the wood, the tool in advanceoperating to reduce the wood to a givendiameter, and the tool whichfollows operating to cut into the cylinder the thread of a screw, or, inother words, cutting a spiral groove along and into the wood, leavingthe thi'eads projecting, These tools may be made to rotate, if' desired,like the cutters commonly used in turning-lasts.

The wood thus shaped is cut into short pieces of the required length,say from sixinches to a foot, and if desired, one end of each block maybe made of any desirable amount of convexity.

In assembling these blocks on a road-bed, six of them surround aseventh, and the threads of the seventh interlock with the threadsformed on each of the six, and each of the six forms the seventhof asurrounding group of six, and this will be the system throughout apavement, except at theborders thereof, as at edge-stones or crosgngs,85c.

' At the pavement boundaries some of the blocks will have to be cut,generally into halves, though some quarter blocks may be required atcorners or angles.

In closing up a space covered with screw-threaded blocks which have beenmade to interlock by pushing them laterally against each other, the lastblocks will be screwed into the spaces left for them between thesurrounding blocks.

This operation will be easily performed by making use of a cross-handledor cranked shaft, having at its other end spurs or teeth, which may beinserted into holes formed in the tops of the screw-threaded blocks, orwhich may be'driven into the wood, and the same tool or implement may beused for removing blocks from the assembled pavement.

In the drawing Figure 1 shows in plan a group of pavementblocks,illustrative of my invention, and

Figures 2 and 3 exhibit the same in elevation.

The form given to the screw-threads may be varied, to suit therequirements of the material and location.

The form shown in fig. 3 is that which I deem best adapted for blocks ofwood.

I claim- A pavement in which the blocks composing it have Witnesses:

J. B. OROsBY, FRANCIS GOULD.

